We all love having fun in the sun — dogs included. But it’s important to be aware of signs of heat injury in dogs and to know how to treat it.

You may already know that signs of heatstroke include excessive panting, staggering, bloody diarrhea, collapse, seizures and shock.

But what veterinarian Dr. Leo Egar wants you to know is how to recognize signs of heat stress early.

Egar, who practices in Phoenix, has been part of the veterinary medical response to several major disasters.

“We want dogs to be able to tolerate some degree of thermal stress as they work and play,” he said at a recent K9 Sport and Scent Work Conference. “Heat stress, or mild heat injury, is a normal reaction to increased exercise or ambient heat.”

When dogs are working or playing, the body produces heat. Thermoregulation is the body’s attempt to balance heat gain and heat loss. A body temperature above 104 degrees F is defined as heat stress; more than 105 as heat exhaustion; and more than 106 as heatstroke.

But body temperature isn’t the only factor to consider.

“You cannot predict heat injury based on body temperature alone,” said Egar. “There’s too much variance between dogs, conditions and measurement methods.”

Knowing your dog’s “normal” temperature is important. For dogs, normal resting temperature can range from 99 to 102.5 degrees. Fit dogs at a moderate activity level might have a body temperature ranging from 104 to 107, depending on individual dog’s metabolism, intensity of activity and ambient temperature.

“This particular range is normal for many fit, working dogs during moderate work and has no adverse effect,” Egar said. “We don’t have a well-defined set point for dogs, but you should know what your dog’s normal is.”

In hot weather, be on the lookout for other signs of heat stress, including decreased moisture on nose tissue, which is caused by dehydration. In addition, dogs that are dehydrated tire more quickly and have less interest in rewards such as treats or play.

Other signs of thermal stress include seeking shade, limiting movement, resting in place, or sprawling on cool ground. If you call an overheated dog, it might be slow to come to you.

Tongue length and uncontrolled panting (when the dog is unable to stop panting) also can signal heat stress. When the tongue is out long and wide, the dog is maximizing surface and airway area to increase evaporation and heat dissipation.

When you see these signs, take action. Start with having your dog sit and try to cool down on its own or with the help of a fan or air conditioning.

Active cooling techniques include hosing down the dog, putting it in water or putting ice packs on it. (The armpits are the best places to apply active cooling because they’re less insulated by fur and have a lot of large blood vessels. Ears can also be good, for the same reasons.)

It’s OK to cool dogs rapidly and to use cold water.

“It’s a common myth that if you take a hot dog and you cool him too quickly, you’ll cause shock,” Egar said. “Not true. Not a single clinical study validates that.”

On a hot day, make sure to take a time out so your dog can drink water and stay hydrated. (Flavored water may encourage your dog to drink more, but electrolyte supplements don’t provide any special benefit.)